Pandemic H1N1 Influenza Infection and Vaccination in Humans Induces Cross-Protective Antibodies that Target the Hemagglutinin Stem

Most monoclonal antibodies (mAbs) generated from humans infected or vaccinated with the 2009 pandemic H1N1 (pdmH1N1) influenza virus targeted the hemagglutinin (HA) stem. These anti-HA stem mAbs mostly used IGHV1-69 and bound readily to epitopes on the conventional seasonal influenza and pdmH1N1 vaccines. The anti-HA stem mAbs neutralized pdmH1N1, seasonal influenza H1N1 and avian H5N1 influenza viruses by inhibiting HA-mediated fusion of membranes and protected against and treated heterologous lethal infections in mice with H5N1 influenza virus. This demonstrated that therapeutic mAbs could be generated a few months after the new virus emerged. Human immunization with the pdmH1N1 vaccine induced circulating antibodies that when passively transferred, protected mice from lethal, heterologous H5N1 influenza infections. We observed that the dominant heterosubtypic antibody response against the HA stem correlated with the relative absence of memory B cells against the HA head of pdmH1N1, thus enabling the rare heterosubtypic memory B cells induced by seasonal influenza and specific for conserved sites on the HA stem to compete for T-cell help. These results support the notion that broadly protective antibodies against influenza would be induced by successive vaccination with conventional influenza vaccines based on subtypes of HA in viruses not circulating in humans.

Genotypic evolution and antigenic drift of H9N2 influenza viruses in China from 1994 to 2008

H9N2 influenza viruses have been circulating in China since 1994, but a systematic investigation of H9N2 in northern China has not been undertaken since 2004. Here, using the sequences of 22 viruses we isolated from poultry and pigs in northern China during 2003-2008, in combination with sequences available in a public database, we analyzed the evolution of H9N2 influenza viruses in China from 1994 to 2008. Our findings demonstrated that the H9N2 viruses in China underwent extensive reassortment, and novel genotypes continued to emerge. Among 330 viruses, 54 genotypes were observed including 19 novel genotypes that have not been recognized before, and major genotypes were further divided into five series (BJ/94-, G1-, BG-, F/98- and Aq-series). Different epidemiological and biological features among these series were recognized. The BJ/94- and F/98-series viruses were circulating in both southern and northern China, while the other three series viruses were mainly detected in southern China. BJ/94-series influenza viruses predominated in China before 2000 and were gradually replaced by F/98-series viruses that became the predominant viruses since 2004. At least five antigenic groups could be identified over the study period, during which a significant antigenic drift likely occurred between 2002 and 2003. Animal experiments demonstrated that F/98-series viruses were able to replicate and transmit more effectively in chickens than BJ/94-series viruses. The continuing evolution of H9N2 influenza viruses in China emphasizes the importance of H9N2 influenza virus surveillance throughout this region to aid pandemic prediction and prevention.

Prototype single step lateral flow technology for detection of avian influenza virus and chicken antibody to avian influenza virus

A rapid and effective lateral flow assay (LFA) for detection of avian influenza virus (AIV) was developed. For antigen capture, the assay used monoclonal antibody specific for a conserved nuclear protein (NP) epitope, immobilized on a cellulose acetate matrix, in conjunction with a second NP monoclonal antibody chemically linked to either coloured latex beads or colloidal gold particles contained in a sample pad for detection. Virus sample added to the sample pad flowed into the trapping antibody to form a visible band as well as a second, control band further along the acetate strip. The control band consisted of recombinant protein A/G, also immobilized on the matrix. A second LFA for detection of chicken antibody to AIV was developed where NP antigen was immobilized on the matrix with recombinant protein A/G immobilized as a control band. Latex beads or colloidal gold particles to which monoclonal anti-chicken antibody was attached, were used as the indicator system.

Effect of increasing energy and protein intake on mammary development in heifer calves

The objective of this study was to determine if increased energy and protein intake from 2 to 14 wk of age would affect mammary development in heifer calves. At 2 wk of age, Holstein heifer calves were assigned to 1 of 4 treatments in a 2 x 2 factorial arrangement with 2 levels of protein and energy intake (moderate, M; high, H) in period 1 (2 to 8 wk of age) and 2 levels of protein and energy intake (low, L; high, H) in period 2 (8 to 14 wk of age), so that mean initial body weights were approximately equal for all 4 treatments (ML, MH, HL, and HH). The M diet in period 1 consisted of a standard milk replacer (21.3% CP, 21.3% fat) fed at 1.1% of BW on a DM basis and a 16.5% CP grain mix fed at restricted intake to promote 400 g of daily gain, whereas the L diet in period 2 consisted only of the grain mix. The H diet in period 1 consisted of a high-protein milk replacer (30.3% CP, 15.9% fat) fed at 2.0% of body weight on a DM basis and a 21.3% CP grain mix available ad libitum. In period 2, the H diet consisted of just the 21.3% grain mix. Calves were gradually weaned from milk replacer by 7 wk and slaughtered at 8 (n = 11) or 14 wk of age (n = 41). Parenchyma from the distal region, midgland, and proximal region relative to the teat from one half of the udder was collected, fixed, and embedded in paraffin. The other half of the gland was used to determine parenchymal mass, protein, fat, DNA, RNA, and extraparenchymal mass. Total parenchymal tissue, parenchymal DNA, parenchymal RNA, and concentrations of DNA and RNA were higher for calves on the H diet during period 1, but were not affected by diet during period 2. Parenchymal fat percentage was increased by the H diet during period 2. The H diet increased extraparenchymal fat during both periods. The area of parenchyma occupied by epithelium was not affected by treatment, but at the end of period 2, the percentage of proliferating epithelial cells as indicated by Ki67, an marker of cell proliferation, expression was greater for calves on the M diet in period 1 compared with calves on the H diet in period 1. Diets did not influence parenchymal protein percentage or the ratio of RNA to DNA. Higher energy and protein intake from 2 to 8 wk of age increased parenchymal mass and parenchymal DNA and RNA in mammary glands of heifer calves without increasing deposition of parenchymal fat. Diet also influenced histological development of mammary parenchyma and subsequent proliferation of ductal epithelial cells. Implications of these effects for future milk production potential are unknown.

Effect of increasing energy and protein intake on body growth and carcass composition of heifer calves

The objective was to determine whether increased energy and protein intake between 2 and 14 wk of age would increase growth rates of heifer calves without fattening. At 2 wk of age, Holstein heifer calves were assigned to 1 of 4 treatments in a 2 x 2 factorial arrangement with 2 levels of protein and energy intake (moderate [M]; high [H]) in period 1 (2 to 8 wk of age) by 2 levels of protein and energy intake (low [L]; high [H]) in period 2 (8 to 14 wk of age) to produce similar initial BW for all 4 treatments. Treatments were ML, MH, HL, and HH, indicating moderate or high energy and protein intake during the first period and low or high intake during the second period. The M diet consisted of a standard milk replacer (21.3% CP, 21.3% fat) fed at 1.1% of BW on a DM basis and a 16.5% CP grain mix fed at restricted intake to promote 400 g of average daily gain (ADG), whereas the L diet consisted only of the grain mix. The H diet consisted of a high-protein milk replacer (30.3% CP, 15.9% fat) fed at 2% of BW on a DM basis and a 21.3% CP grain mix available ad libitum. Calves were weaned gradually from milk replacer by 7 wk and slaughtered at 8 (n = 11) or 14 wk of age (n = 41). In periods 1 and 2, ADG and the gain:feed ratio were greater for calves fed the H diet. Calves fed the H diet were taller after both periods 1 and 2. No difference was observed in carcass composition at 8 wk, but at 14 wk calves fed MH and HH had less water and more fat than calves fed ML and HL. Plasma IGF-I concentrations were greatest for calves fed the H diet during either period. Plasma leptin concentrations were increased in calves fed the H diet during period 1 from 4 to 6 wk of age. Increasing energy and protein intake from 2 to 8 wk and 8 to 14 wk of age increased BW, withers height, and gain:feed ratio. Calves fed the H diet from 8 to 14 wk of age had more body fat than calves fed the L diet. Increased energy and protein intake can increase the rate of body growth of heifer calves and potentially reduce rearing costs.

Introducing triage logic as a new strategy for the detection of signals in the WHO Drug Monitoring Database

PURPOSE

An important role for the WHO Programme for International Drug Monitoring is to identify signals of international drug safety problems as early as possible. The signal detection strategy, operated at the Uppsala Monitoring Centre (UMC), gave too many drug-adverse drug reaction (ADR) combinations for individual review. Therefore additional selection strategies were needed to improve the likely signal-to-noise ratio and for the UMC to complement the efforts of national centres in an efficient way.

METHODS

The combinations database of the first quarter of 2001 was analysed using algorithms representing different strategies for finding relevant signals using triage logic.

RESULTS

The strategies that together gave a manageable number of combinations, i.e. around 600, for further consideration in a single quarter were the algorithms for 'Rapid reporting increase', 'Serious reaction and new drug' and 'Special interests'. These filters began to be used routinely on the combinations database in late 2001.

CONCLUSIONS

While stressing that human review is essential, triage strategies are useful when attempting analysis of large amounts of data. By definition, the use of triage strategies may exclude some potential signals from consideration, although the intention is to improve the chances of detection by focussing on areas of greatest importance.

Pattern of mutation in the genome of influenza A virus on adaptation to increased virulence in the mouse lung: identification of functional themes

The genetic basis for virulence in influenza virus is largely unknown. To explore the mutational basis for increased virulence in the lung, the H3N2 prototype clinical isolate, A/HK/1/68, was adapted to the mouse. Genomic sequencing provided the first demonstration, to our knowledge, that a group of 11 mutations can convert an avirulent virus to a virulent variant that can kill at a minimal dose. Thirteen of the 14 amino acid substitutions (93%) detected among clonal isolates were likely instrumental in adaptation because of their positive selection, location in functional regions, and/or independent occurrence in other virulent influenza viruses. Mutations in virulent variants repeatedly involved nuclear localization signals and sites of protein and RNA interaction, implicating them as novel modulators of virulence. Mouse-adapted variants with the same hemagglutinin mutations possessed different pH optima of fusion, indicating that fusion activity of hemagglutinin can be modulated by other viral genes. Experimental adaptation resulted in the selection of three mutations that were in common with the virulent human H5N1 isolate A/HK/156/97 and that may be instrumental in its extreme virulence. Analysis of viral adaptation by serial passage appears to provide the identification of biologically relevant mutations.

Reovirus sigmaNS protein is required for nucleation of viral assembly complexes and formation of viral inclusions

Progeny virions of mammalian reoviruses are assembled in the cytoplasm of infected cells at discrete sites termed viral inclusions. Studies of temperature-sensitive (ts) mutant viruses indicate that nonstructural protein sigmaNS and core protein mu2 are required for synthesis of double-stranded (ds) RNA, a process that occurs at sites of viral assembly. We used confocal immunofluorescence microscopy and ts mutant reoviruses to define the roles of sigmaNS and mu2 in viral inclusion formation. In cells infected with wild-type (wt) reovirus, sigmaNS and mu2 colocalize to large, perinuclear structures that correspond to viral inclusions. In cells infected at a nonpermissive temperature with sigmaNS-mutant virus tsE320, sigmaNS is distributed diffusely in the cytoplasm and mu2 is contained in small, punctate foci that do not resemble viral inclusions. In cells infected at a nonpermissive temperature with mu2-mutant virus tsH11.2, mu2 is distributed diffusely in the cytoplasm and the nucleus. However, sigmaNS localizes to discrete structures in the cytoplasm that contain other viral proteins and are morphologically indistinguishable from viral inclusions seen in cells infected with wt reovirus. Examination of cells infected with wt reovirus over a time course demonstrates that sigmaNS precedes mu2 in localization to viral inclusions. These findings suggest that viral RNA-protein complexes containing sigmaNS nucleate sites of viral replication to which other viral proteins, including mu2, are recruited to commence dsRNA synthesis.

The murine double-stranded RNA-dependent protein kinase PKR is required for resistance to vesicular stomatitis virus

Interferon (IFN)-induced antiviral responses are mediated through a variety of proteins, including the double-stranded RNA-dependent protein kinase PKR. Here we show that fibroblasts derived from PKR(-/-) mice are more permissive for vesicular stomatitis virus (VSV) infection than are wild-type fibroblasts and demonstrate a deficiency in alpha/beta-IFN-mediated protection. We further show that mice lacking PKR are extremely susceptible to intranasal VSV infection, succumbing within days after instillation with as few as 50 infectious viral particles. Again, alpha/beta-IFN was unable to rescue PKR(-/-) mice from VSV infection. Surprisingly, intranasally infected PKR(-/-) mice died not from pathology of the central nervous system but rather from acute infection of the respiratory tract, demonstrating high virus titers in the lungs compared to similarly infected wild-type animals. These results confirm the role of PKR as the major component of IFN-mediated resistance to VSV infection. Since previous reports have shown PKR to be nonessential for survival in animals challenged with encephalomyocarditis virus, influenza virus, and vaccinia virus (N. Abraham et al., J. Biol. Chem. 274:5953-5962, 1999; Y. Yang et al., EMBO J. 14:6095-6106, 1995), our findings serve to highlight the premise that host dependence on the various mediators of IFN-induced antiviral defenses is pathogen specific.

Reovirus mu2 protein determines strain-specific differences in the rate of viral inclusion formation in L929 cells

Reovirus infection induces the formation of large cytoplasmic inclusions that serve as the major site of viral assembly. Reovirus strains type 3 Dearing (T3D) and type 1 Lang (T1L) differ in the rate of inclusion formation in L929 cells. The median time of inclusion formation is 18 h in cells infected with T3D and 39 h in cells infected with T1L. Using reassortant viruses that contain combinations of gene segments derived from T1L and T3D, we found that the M1 gene, which encodes the mu2 protein, is the primary determinant of the rate of inclusion formation. The S3 gene, which encodes the nonstructural protein sigmaNS, plays a secondary role in this process. The subcellular location of the mu2 protein was determined by confocal laser scanning microscopy using dual-fluorescence labeling of mu2 and the outer-capsid protein mu1/mu1C. In virus-infected cells, mu2 protein colocalized with other viral proteins in inclusions and was also distributed diffusely in the cytoplasm and nucleus. Expression of recombinant T1L and T3D mu2 proteins resulted in the formation of protein complexes resembling inclusions in both the cytoplasm and the nucleus with kinetics that reflected the strain of origin. The median time of mu2 protein complex formation was 22 h in cells transfected with the T3D M1 gene and 43 h in cells transfected with the T1L M1 gene. These findings suggest that the mu2 protein influences the rate of inclusion formation and contributes to inclusion morphogenesis. The requirement of mu2 protein in inclusion formation was tested by determining the subcellular localization of mu2 in cells infected with temperature-sensitive (ts) mutants that are defective in viral assembly. In contrast to infection with wild-type virus, mu2 did not colocalize with mu1/mu1C protein in subcellular structures that formed in cells infected at nonpermissive temperature with ts mutants tsH11.2, tsC447, and tsG453 with mutations in the M1, S2, and S4 genes, respectively. These results suggest that despite the role of the mu2 protein in controlling the rate of inclusion formation, this process is a concerted function of several reovirus proteins.

Evaluation of a neonatal rat model for prediction of mumps virus neurovirulence in humans

Neurovirulence of several mumps virus strains was assessed in a prototype rat neurovirulence test and compared to results obtained in the monkey neurovirulence test. The relative human neurovirulence of these strains was proportional to the severity of hydrocephalus in rats but not to lesion scores in the monkeys.

Influenza virus genetics

Significant progress has been made in understanding the process of influenza A virus replication in cell culture; however, much less is known about the genetic control of virus-host interactions in disease. This review provides an overview of the genetic analysis of influenza virus biology. The functional map of the individual genes of influenza A virus is presented as well as the status of our current understanding of pathogenesis. Influenza has a segmented genome so it is possible to obtain reassortants that contain novel combinations of genome segments derived from different viruses. This is a very useful genetic tool and is also an important aspect of influenza evolution and biology. Human influenza viruses originate from avian strains of influenza virus so that influenza infection is at its basis a zoonosis. Influenza virus strains are host-restricted, however, and avian strains must be adapted to the human host. So questions of host-range and interaction with host factors are important determinants of the ability of influenza virus to cause disease in humans. Host-range is restricted primarily due to host-specific interactions of the ribonucleocapsid and the viral receptor. There are two classes of drugs for inhibiting influenza infection, amantadine HCl and neuraminidase inhibitors. The mode of action and basis for resistance to these drugs are presented. Prospective targets for antiviral therapy are also discussed.

Heteroduplex mobility assay-guided sequence discovery: elucidation of the small subunit (18S) rDNA sequences of Pfiesteria piscicida and related dinoflagellates from complex algal culture and environmental sample DNA pools

The newly described heterotrophic estuarine dinoflagellate Pfiesteria piscicida has been linked with fish kills in field and laboratory settings, and with a novel clinical syndrome of impaired cognition and memory disturbance among humans after presumptive toxin exposure. As a result, there is a pressing need to better characterize the organism and these associations. Advances in Pfiesteria research have been hampered, however, by the absence of genomic sequence data. We employed a sequencing strategy directed by heteroduplex mobility assay to detect Pfiesteria piscicida 18S rDNA "signature" sequences in complex pools of DNA and used those data as the basis for determination of the complete P. piscicida 18S rDNA sequence. Specific PCR assays for P. piscicida and other estuarine heterotrophic dinoflagellates were developed, permitting their detection in algal cultures and in estuarine water samples collected during fish kill and fish lesion events. These tools should enhance efforts to characterize these organisms and their ecological relationships. Heteroduplex mobility assay-directed sequence discovery is broadly applicable, and may be adapted for the detection of genomic sequence data of other novel or nonculturable organisms in complex assemblages.

Biological characteristics of genetic variants of Urabe AM9 mumps vaccine virus

The Urabe AM9 mumps vaccine is composed of a mixture of variants distinguishable by a difference at nucleotide (nt) 1081 of the hemagglutinin-neuraminidase (HN) gene (Brown, E.G., Dimock, K., Wright, K.E., 1996. The Urabe AM9 mumps vaccine is a mixture of viruses differing at amino acid (aa) 335 of the hemagglutinin-neuraminidase gene with one form associated with disease. J. Infect. Dis. 174, 619-622.). Further genetic and biological variation was detected in plaque purified viruses from the Urabe AM9 vaccine by examining the HN gene sequence, plaque morphology, cytopathic effects and growth in Vero cells, and temperature sensitivity (ts). Infection of Vero cells with plaque purified viruses with a G at nt 1081 of the HN gene produced large, clear plaques, caused significant CPE early after infection but yielded lower titres of virus than other purified viruses. None of these viruses were ts. In contrast, half of the plaque purified viruses with an A at nt 1081 were sensitive to a temperature of 39.5 degrees C. These viruses produced small plaques, caused significant CPE and grew to low titres. Two ts viruses possessed a unique aa substitution at aa 468 of HN. The remaining A(1081) viruses were not ts, produced large plaques but little CPE, and grew to titres 10-fold higher than the G(1081) viruses. Isolates of Urabe AM9 associated with post-vaccination illness were similar to these non-ts A(1081) viruses, but could be further sub-divided into two groups on the basis of a difference at aa 464 of HN. The post-vaccination isolates may represent insufficiently attenuated components of the vaccine, while the G(1081) and ts subset of A(1081) viruses may be more fully attenuated.

The mumps virus neurovirulence safety test in Rhesus monkeys: a comparison of mumps virus strains

Wild type mumps viruses are highly neurotropic and a frequent cause of aseptic meningitis in unvaccinated humans. To test whether attenuated mumps viruses used in the manufacture of mumps vaccines have neurovirulent properties, a monkey neurovirulence safety test (MNVT) is performed. However, results with several mumps virus MNVTs have raised questions as to whether the test can reliably discriminate neurovirulent from nonneurovirulent mumps virus strains. Here, various mumps virus strains representing a wide range of neuropathogenicity were tested in a standardized MNVT. A trend of higher neurovirulence scores was observed in monkeys inoculated with wild type mumps virus versus vaccine strains, although differences were not statistically significant. Results indicated the need for further examination and refinement of the MNVT or for development of alternative MNVTs.

Genetic analysis of mouse-adapted influenza A virus identifies roles for the NA, PB1, and PB2 genes in virulence

Adaptation of the prototype A/FM/1/47 H1N1 strain to mice resulted in selection of the A/FM/1/47-MA variant with increased virulence. Earlier analysis identified mutations in the HA and M1 genes that increase virulence in the mouse. Complete sequence analysis identified mutations in the PB1, PB2, HA, NA, and M1 genes. Reassortants were produced between the parental FM and FM-MA strains to obtain viruses that differ due to combinations of mutant genes. To assess the relationship between virulence and replication, the median lethal dose was determined for mice and growth properties were assessed in mouse lung, MDCK cells and chicken embryo. Not only were all five mutations shown to control virulence but also the replicative capacity in the mouse. The HA, NA and M1 mutations increased yield in all three hosts whereas in combination the PB1 and PB2 mutations were host restrictive changing the virus to a mouse specific strain. For the NA and M1 mutations the increase in growth in mouse lung was proportional to a 2-fold (log10) increase in virulence however the HA mutation increased virulence largely independent of increased growth indicating a change in pathological properties that damage the host. Thus mutations that affect virulence can be classified according to host-dependent and independent ability to increase growth as well as changes in pathological properties. Each of the PB1, PB2, NA, HA, and M1 genes acquired gain-of-function mutations for mouse infection that involve structural motifs that may serve as markers for virulence or targets for antiviral therapy.

Immunochemical localization of platelet-derived growth factor in placenta and its possible role in pre-eclampsia

BACKGROUND

Platelet-derived growth factor (PDGF) has an important role in cellular function, proliferation, and angiogenesis. It is also associated with tissue injury and repair, and its involvement in atherosclerosis has been studied extensively. Tissue injury is also found in pre-eclampsia (PRE). The morphological and physiological changes that are taking place in the PRE placenta may be associated with this growth factor. The objective of this study was to determine if PDGF-AA and its alpha receptor are present in the cells and vessels of normotensive (NORM) and PRE placentas at term.

METHODS

Placental tissue was obtained from 6 preeclamptic and 8 normotensive women. Gestational age ranged from 38-42 weeks. Deliveries were either vaginal (vag, n = 10) or c-section (c-sec, n = 4). Tissue samples were analyzed for PDGF-AA by immunocytochemistry.

RESULTS

PDGF-AA and the alpha receptor were present in both NORM and PRE placentas. Immunoreactive staining revealed PDGF-AA and its receptor in the intimal/endothelial layer of fetal vessels and the trophoblastic layer. Staining intensity was greater in preeclamptic tissue when obliterative endarteritis was present.

CONCLUSIONS

In pre-eclampsia, PDGF-AA may play a role in the restructuring of the fetoplacental vasculature, in particular when there is inflammation of the vascular intimal layer, as found in obliterative endarteritis. Increased staining in the trophoblast layer in patients with obliterative endarteritis also may be indicative of more widespread damage throughout the placenta itself, and PDGF-AA may play a significant role in the repair of this damage.

Characterization of transgenic mice with targeted disruption of the catalytic domain of the double-stranded RNA-dependent protein kinase, PKR

The interferon-inducible, double-stranded RNA-dependent protein kinase PKR has been implicated in anti-viral, anti-tumor, and apoptotic responses. Others have attempted to examine the requirement of PKR in these roles by targeted disruption at the amino terminal-encoding region of the Pkr gene. By using a strategy that aims at disruption of the catalytic domain of PKR, we have generated mice that are genetically ablated for functional PKR. Similar to the other mouse model of Pkr disruption, we have observed no consequences of loss of PKR on tumor suppression. Anti-viral response to influenza and vaccinia also appeared to be normal in mice and in cells lacking PKR. Cytokine signaling in the type I interferon pathway is normal but may be compromised in the erythropoietin pathway in erythroid bone marrow precursors. Contrary to the amino-terminal targeted Pkr mouse, tumor necrosis factor alpha-induced apoptosis and the anti-viral apoptosis response to influenza is not impaired in catalytic domain-targeted Pkr-null cells. The observation of intact eukaryotic initiation factor-2alpha phosphorylation in these Pkr-null cells provides proof of rescue by another eukaryotic initiation factor-2alpha kinase(s).

The medical dictionary for regulatory activities (MedDRA)

The International Conference on Harmonisation has agreed upon the structure and content of the Medical Dictionary for Regulatory Activities (MedDRA) version 2.0 which should become available in the early part of 1999. This medical terminology is intended for use in the pre- and postmarketing phases of the medicines regulatory process, covering diagnoses, symptoms and signs, adverse drug reactions and therapeutic indications, the names and qualitative results of investigations, surgical and medical procedures, and medical/social history. It can be used for recording adverse events and medical history in clinical trials, in the analysis and tabulations of data from these trials and in the expedited submission of safety data to government regulatory authorities, as well as in constructing standard product information and documentation for applications for marketing authorisation. After licensing of a medicine, it may be used in pharmacovigilance and is expected to be the preferred terminology for international electronic regulatory communication. MedDRA is a hierarchical terminology with 5 levels and is multiaxial: terms may exist in more than 1 vertical axis, providing specificity of terms for data entry and flexibility in data retrieval. Terms in MedDRA were derived from several sources including the WHO's adverse reaction terminology (WHO-ART), Coding Symbols for a Thesaurus of Adverse Reaction Terms (COSTART), International Classification of Diseases (ICD) 9 and ICD9-CM. It will be maintained, further developed and distributed by a Maintenance Support Services Organisation (MSSO). It is anticipated that using MedDRA will improve the quality of data captured on databases, support effective analysis by providing clinically relevant groupings of terms and facilitate electronic communication of data, although as a new tool, users will need to invest time in gaining expertise in its use.

The reovirus protein mu2, encoded by the M1 gene, is an RNA-binding protein

The reovirus M1, L1, and L2 genes encode proteins found at each vertex of the viral core and are likely to form a structural unit involved in RNA synthesis. Genetic analyses have implicated the M1 gene in viral RNA synthesis and core nucleoside triphosphatase activity, but there have been no direct biochemical studies of mu2 function. Here, we expressed mu2 in vitro and assessed its RNA-binding activity. The expressed mu2 binds both poly(I-C)- and poly(U)-Sepharose, and binding activity is greater in Mn2+ than in Mg2+. Heterologous RNA competes for mu2 binding to reovirus RNA transcripts as effectively as homologous reovirus RNA does, providing no evidence for sequence-specific RNA binding by mu2. Protein mu2 is now the sixth reovirus protein demonstrated to have RNA-binding activity.

Interference by a non-defective variant of influenza A virus is due to enhanced RNA synthesis and assembly

Mouse-adapted influenza A virus, FM-MA, interferes with the replication of wild-type strains on co-infection. The interference phenotype was previously mapped to FM-MA segment 2 encoding a mutant PB1 protein, the catalytic component of the RNA polymerase complex. To identify the point at which FM-MA interferes with wild-type A/HK/1/68 (HK), the relative levels of transcription and genome replication of the PB1, NP and M1 genes were determined for FM-MA and HK viruses in co-infected cells using RT-PCR. All stages of HK macromolecular synthesis (primary and secondary transcription, genomic RNA, complementary RNA and protein synthesis) were suppressed relative to FM-MA. Infection with HK virus alone resulted in the accumulation of similar or greater amounts of RNA at late times post-infection relative to FM-MA thus indicating that the presence of FM-MA specifically compromised HK transcription and replication in co-infected cells. However early in infection FM-MA was ten times more active in mRNA transcription than HK or its parental strain FM. FM-MA's ability to interfere was primarily due to an increased capacity for primary transcription. FM-MA genomes were also selectively assembled into progeny virus from cells co-infected with HK and FM-MA, a step which was distinct from the capacity for enhanced RNA synthesis. This suggests that interference of HK growth by FM-MA in mixed infections results from two distinct events: a preferential synthesis of FM-MA-specific macromolecules which is then augmented by a preferential assembly of FM-MA genomes.

Genetic studies on a mumps vaccine strain associated with meningitis

Vaccination with mumps measles and rubella (MMR) vaccine containing the live attenuated mumps strain, Urabe AM9, is associated with an increased incidence of meningitis. The isolation of mumps virus from CSF and subsequent identification as Urabe AM9-like by sequence analysis confirmed the causative role of Urabe AM9 vaccine in meningitis. To assess the role of genetic reversion in vaccine failure, sequence comparisons were made between several genes of Urabe AM9 vaccine and post-vaccination meningitis mumps isolates. An amino acid substitution in the Urabe AM9 HN gene Lys335Glu was not detected in the post-vaccination meningitis isolates suggesting that reversion to wild type sequence was associated with vaccine failure. However, further analysis showed that the vaccine was a mixture of viruses that differed at aa 335 of HN, possessing either the wild type Lys335 or the mutant Glu335, whereas the clinical isolates were homogeneous and possessed the wild type Lys335. Passage of the Urabe AM9 vaccine preparations in Vero cells resulted in the amplification of the Glu335 virus, however the post-vaccination meningitis isolates (Lys335) grew better in Vero cells than Urabe AM9 vaccine. A virus isolate, similar to the post-vaccination isolates was obtained from the vaccine suggesting that the strain responsible for vaccine failure was a pre-existing component of the vaccine and was not necessarily the result of reversion. The Urabe AM9 vaccine is a heterogeneous mixture of genotypes that differ in virulence with the HN Glu335 viruses being attenuated and at least a subset of the HN Lys335 viruses that are associated with disease. The Glu335 mutation may be among a class of attenuating mutations identified in several neurotropic viruses that involve charged amino acids in neutralising epitopes of receptor binding proteins. Copyright 1998 John Wiley & Sons, Ltd.

Expression of platelet-derived growth factor-A mRNA in human placenta: effect of magnesium infusion in pre-eclampsia

The expression of platelet-derived growth factor-A (PDGF-A) mRNA was examined in the cotyledons of normal human placentae and those from patients with pre-eclampsia. These patients exhibited pre-delivery blood pressure of 154+/-4/99+/-4 mmHg (mean+/-SEM) and met the criteria established for pre-eclampsia. During labour they received MgSO4 infusion for various time intervals (4-25 h). The PDGF-A message was quantitated to beta-actin by the solution hybridization nuclease protection assay. Since the two groups differed in two parameters (pre-eclampsia and MgSO4 treatment), the direct comparison was not feasible. An analysis of covariance revealed a significant difference in the message between the pre-eclamptic and control groups (P<0.01); the gestational age was not a significant covariate for either group but the time on MgSO4 in pre-eclampsia group was significant (P<0.002). A linear regression analysis of PDGF-A mRNA values for the pre-eclamptic group showed a time-dependent downregulation of the message by MgSO4 (P<0.01, r=- 0.796). These results show a uniform expression of PDGF-A mRNA in cotyledons of normal human placenta between 35 and 40 weeks of gestation. Furthermore, MgSO4 has an inhibitory effect on the expression of this message which may have aside from its anticonvulsive action beneficial effect on the function of pre-eclamptic placenta.

Arteriovenous extracorporeal carbon dioxide removal: a mathematical model and experimental evaluation

To explore the feasibility and operating limits of arteriovenous extracorporeal CO2 removal (AVCO2R) for support of acute respiratory failure, the authors developed a mathematical model to simulate (AVCO2R), evaluate the effects of several parameters used in its application, and predict the feasibility and necessary conditions for total CO2 removal. The mathematical model incorporated compartments representing blood, pulmonary alveoli, pulmonary capillaries, peripheral tissues and capillaries, and an extracorporeal gas exchange device. The model was validated against an animal model of extracorporeal CO2 removal. This model consisted of anesthetized and mechanically ventilated piglets. An extracorporeal CO2 removal device was placed by cannulation of a femoral artery and vein. Dynamic and steady state measurements of CO2 transfer were made and compared with simulations using the mathematical model. There was good agreement between experimental and simulated data, validating the mathematical model under a variety of conditions. The mathematical model was used to determine operating parameters for total CO2 removal. Relationships between extracorporeal blood flow, device diffusing capacity, and device gas sweep flow were established for CO2 removal at various levels of CO2 production. These simulations indicate that it is possible to achieve total CO2 removal using an extracorporeal shunt fraction of 10%-15% of cardiac output, a device diffusing capacity of 0.5 ml x min(-1) x torr(-1) (kg body weight)(-1), and a gas:blood flow of 5 or greater.

Selective use of vancomycin to prevent coagulase-negative staphylococcal nosocomial bacteremia in high risk very low birth weight infants

OBJECTIVE

To determine whether vancomycin added to parental nutrition (PN) fluids could prevent nosocomial infections in very low birth weight newborns and which infants would benefit most from prophylaxis.

DESIGN

Double blind, randomized controlled study.

SETTING AND STUDY POPULATION

Very low birth weight infants receiving PN in a tertiary neonatal intensive care unit.

METHODS

Thirty-eight infants with and without central vascular catheters were randomized to receive no medication or 25 microg/ml vancomycin added to PN for the duration of the infant's PN requirements.

RESULTS

The addition of 25 microg/ml vancomycin to PN prevented bacteremia in very low birth weight infants receiving PN. There was a significant reduction in the number of coagulase-negative staphylococcal (CONS) bacteremias (defined as isolation of the same organism from two positive blood cultures) during PN (5 vs. 0; P = 0.037) as well as the total number of bacteremias and fungemias (9 vs. 1; P = 0.036). The total number of hospital days (108 +/- 13 vs. 76 +/- 6; P = 0.039) were reduced in infants receiving vancomycin. Infants with birth weights of < 1000 g who received corticosteroids for treatment of chronic lung disease benefitted most from treatment. No vancomycin-resistant strains of CONS or enterococci were detected during the study period.

CONCLUSIONS

Prophylactic treatment with vancomycin effectively prevented CONS bacteremia under the conditions of the study. Its use was most effective in infants with birth weights of <1000 g.

Mutations in the hemagglutinin and matrix genes of a virulent influenza virus variant, A/FM/1/47-MA, control different stages in pathogenesis

The mouse adapted strain of influenza A/FM/1/47 virus, FM-MA, has increased virulence due to mutations in HA, M1 and at least one other, unmapped, genome segment. Genetic reassortants that differ due to the HA or M1 mutations were used to define the role of these mutations in pathogenesis. Pathological changes in lungs of infected mice were assessed by hematoxylin phloxine saffron (HPS) staining, and viral infection was measured by fluorescent antibody staining of thin sections and flow cytometry of lung parenchymal cells. HA played a role in bronchiolar pathology by increasing necrosis of bronchiolar epithelium, peribronchiolar lymphocytes, and airway obstruction. The HA mutation was shown to be responsible for a 0.2 unit decreased in the pH optimum of fusion and controlled resistance to alpha and beta inhibitors of hemagglutination. Both these changes in biology may confer a replicative advantage in bronchioles seen in the first day of infection. Thus the HA mutation may have conferred a survival advantage in the extracellular lung environment. The M1 mutation resulted in improved growth in the lung and cultured cells and was associated with increases in recruitment of macrophages, spread of infection into the alveoli of the lung and interstitial pneumonia. Sequence analysis indicated that the unmapped mutation in the control of FM-MA virulence is either the K482-->R substitution in the PB2 protein or the D538-->G substitution in the PB1 protein. One or other of these mutations results in a growth advantage in infected lung but not in cultured cells as well as a further increased recruitment and infection of macrophages in the lung. Infection with virulent strains of influenza that induced increases in macrophage recruitment caused hypothermia in the mouse.

The Urabe AM9 mumps vaccine is a mixture of viruses differing at amino acid 335 of the hemagglutinin-neuraminidase gene with one form associated with disease

The reason for the high incidence of vaccine-associated meningitis due to the Urabe AM9 vaccine was assessed by comparing the nucleotide (nt) sequence of the hemagglutinin-neuraminidase (HN) gene from vaccine virus to those of viruses isolated from persons with postvaccination meningitis. A G1081--> A nt substitution that was predicted to result in a Glu335--> Lys reversion in the HN protein was detected between Urabe AM9 (G) and postvaccine meningitis mumps virus isolates (A). Further analysis showed that the Urabe AM9 vaccine was a mixture of viruses with wild type (A) and variant (G) nt at position 1081. Urabe AM9 vaccinees who developed meningitis or parotitis possessed predominantly A (98%-100%) at nt 1081, indicating strong selection of the wild type (A) form relative to the variant (G) form. Mumps virus homogeneous for the variant Glu335 form of the HN gene may be safer than the original Urabe AM9 vaccine.

Thyroglossal duct cyst causing airway obstruction in an adult

Thyroglossal duct cysts, though not uncommon, rarely present with evidence of laryngeal compromise. The case presented is one of the very few cases with documented laryngeal invasion reported in the English language. Of clinical significance is the patient's presentation with laryngeal symptoms of choking and dysphonia in the presence of a small anterior cervical mass. While the thyroglossal duct cyst usually presents as an asymptomatic anterior neck mass, this case illustrates the importance of considering a thyroglossal duct cyst in any patient with airway compromise in the absence of a neck mass.

Stable expression of the reovirus mu2 protein in mouse L cells complements the growth of a reovirus ts mutant with a defect in its M1 gene

Reovirus mu2 protein was constitutively expressed in mammalian cells transfected with dicistronic constructs in which the reovirus M1 gene and the selectable neomycin-resistant gene (neo) were both driven by the same phosphoglycerate kinase promoter. Translation of neo was initiated with the cap-independent translation initiation element from encephalomyocarditis virus. Expression of mu2 protein was detected by mu2-specific antibody produced through immunization of rabbits with Trp-E-mu2 fusion proteins expressed in Escherichia coli. The expression levels of mu2 proteins of serotype 1 (T1) and serotype 3 (T3) were different and varied in different mouse cell lines with T1 being expressed more efficiently than T3. mu2 expressing L929 cell lines generated with the dicistronic constructs were highly stable. Inclusion of the transforming fragment of bovine papillomavirus in the dicistronic construct lead to higher levels of mu2 expression that were less stable and thus decreased on continued cell culture. The mu2 protein expressed in transfectants was authentic as shown by peptide mapping comparison with mu2 protein from reovirus-infected cells and that from in vitro transcription and translation of the M1 gene. It was further shown that the mu2 protein expressed in a stable L929 cell line complemented the growth of the reovirus tsH11.2 mutant with a defect in its M1 gene. It is concluded that the mu2 protein stably expressed by transfection is functionally equivalent to mu2 protein expressed by reovirus.

Translation of the reovirus M1 gene initiates from the first AUG codon in both infected and transfected cells

Reovirus mu 2 protein can be expressed via the mouse phosphoglycerate kinase promoter to low levels in stably transfected L cells. To increase mu 2 expression, the terminal regions of the M1 gene cDNA constructs were modified and the effect on mu 2 expression was analyzed. The M1 gene has a single large open reading frame beginning at nucleotide 14 with another, in frame, AUG codon at nucleotide 161 reported to be used for translation initiation. Unexpectedly, deletions of the M1 5' terminal sequence upstream of the reported translation initiation codon, AUG161, resulted in loss of detection of mu 2 expression. When expression was driven by the stronger T7 promoter in the presence of recombinant vaccinia virus expressing the T7 RNA polymerase, constructs with the M1 5'-terminal deletion produced a smaller protein product of approximately 68 kDa, compared to approximately 73 kDa for the protein produced from the full-length M1-containing constructs consistent with the loss of 49 amino acids. The amount of shorter mu 2 product was increased by producing an improved 'Kozak' consensus sequence around the AUG codon at nucleotide 161 or by introducing an internal ribosome entry site at this location. Full-length M1 gene constructs produced a protein of the same size as the authentic mu 2 protein from virus-infected cells. It was further shown that the approximately 73 kDa product was expressed when the M1 gene was in different plasmid backgrounds and even when the M1 gene transcript was preceded by a 1 kb gene. This study demonstrated that translation of the reovirus M1 gene initiates from the first AUG codon in both infected and transfected cells.

Augmentation of murine hematopoiesis by interleukin 2-activated irradiated T cells

We have examined the role of T cells activated with interleukin-2 (IL-2) in vitro and subsequently irradiated (2500 rads), in stimulating murine hematopoiesis in a syngeneic system. Our data suggest that activated, irradiated T (AIT) cells significantly increased the progenitor cell activity of T cell-depleted bone marrow (BM) both in vitro and in vivo as compared with controls (P < 0.001). The efficacy of AIT cells was comparable to that of activated, nonirradiated T (AT) cells (P > 0.05). Optimal stimulation of BM progenitor cell activity was seen when T cells were activated for 4 days and used in a BM to T cell ratio of 1:2 or 1:5. The effect of these activated cells was related to the release of factors with ability to enhance hematopoiesis. These observations may have implications in enhancing the engraftment of T cell-depleted BM in allogeneic transplantation.

Successful prenatal management of hydrops, caused by congenital cystic adenomatoid malformation, using serial aspirations

Congenital cystic adenomatoid malformation (CCAM) is a lung lesion that is now commonly diagnosed in utero with fetal ultrasonography. The described treatment of this lesion includes observation with treatment delivery, a single aspiration, thoraco-amniotic shunts, and fetal resection. This patient had an in utero diagnosis of a Stocker type I CCAM associated with hydrops. Fetal resection was not an option because of patient refusal. The fetus was treated with multiple serial aspirations. There was marked improvement of the anasarca, and subsequently the baby was born without respiratory distress. On the second day of life the CCAM began to expand, and the right lower lobe was resected. The baby's postoperative course was uneventful. CCAM with hydrops is associated with a high mortality rate. Current recommended therapy for these lesions is fetal resection or thoracoamniotic shunt. The authors' patient was treated with serial fetal thoracocenteses, with an excellent outcome. This therapy may be an alternative to fetal surgery or an adjunct to fetal surgery in selected cases.

Role of granulocyte colony-stimulating factor in preventing ceftazidime-induced myelosuppression in vitro

Ceftazidime has been reported to cause myelosuppression both in vitro and in vivo. Granulocyte colony-stimulating factor (G-CSF) is known to enhance the proliferation and differentiation of myeloid cells. The present study was carried out to define the role of G-CSF in preventing the ceftazidime-induced suppression of BM progenitor cells in vitro, and to define the mechanisms involved in ceftazidime-induced myelosuppression. Our results show that G-CSF was able to maintain the proliferative activity of BM cells in the presence of ceftazidime if it was added to the culture medium during the early phase of exposure of BM to ceftazidime. Monoclonal antibody to TNF completely inhibited the ceftazidime-induced myelosuppression. The suppressive effect on BM was mediated via CD3+ T cells whereas macrophages conferred protection against this suppression. TNF-induced suppression of BM was inhibited by G-CSF. These data suggest that G-CSF prevents the ceftazidime-induced myelosuppression by antagonizing the suppressive effect of TNF and by enhancing the proliferative activity of BM.

Induction of antitumor effect by treatment with cyclosporine A plus interferon-gamma after chemotherapy: role of cytotoxic cells

We have previously shown that administration of cyclosporine A (CsA) plus interferon-gamma (IFN) after chemotherapy to mice bearing B16 melanoma results in the generation of cells with major histocompatibility complex (MHC)-unrestricted cytotoxicity in vitro and in vivo; the antitumor effect of these cells could be attenuated by normal spleen cells. This study shows that antitumor effect after treatment with CsA plus IFN after chemotherapy was mediated by T and natural killer (NK) cells, both in vitro and in vivo. Infusion of purified T or NK cells into secondary recipients after chemotherapy resulted in a significant control in the dissemination of tumor as compared to chemotherapy alone. The antitumor potential of NK cells was at least 10 times greater than that of T cells. The effector cells could inhibit the proliferation of tumor cells in vitro without a contact between the effector and tumor cells, suggesting that antitumor effect in this system was partly related to the secretion of cytotoxic factors by the effector cells. Infusion of normal spleen cells inhibited the antitumor effect of adoptively transferred effector cells. This study defines the nature of effector cells involved in mediating the antitumor effect in this model; the optimal efficacy of these cells in the recipient is possibly related to the abolition of a suppressor system by chemotherapy.

Protective effect of granulocyte-colony stimulating factor against amphotericin B-induced myelosuppression in vitro

Amphotericin B causes suppression of bone marrow (BM) progenitor cells in vitro. Granulocyte colony stimulating factor (G-CSF) enhances the proliferation of myeloid cells. The present study defines the role of G-CSF in preventing amphotericin B-induced myelosuppression. G-CSF increased the proliferative potential of BM and protected against amphotericin B-induced myelosuppression if it was added to the medium during the early phase of exposure of BM to amphotericin B. Monoclonal antibodies to tumour necrosis factor-alpha (TNF) or interferon-gamma (IFN) inhibited the myelosuppression partially; simultaneous presence of both these antibodies completely abrogated this suppression, suggesting that both TNF alpha and IFN gamma were involved in amphotericin-induced myelosuppression. TNF- or IFN-induced suppression of BM was also inhibited by G-CSF. These data suggest that G-CSF prevents the amphotericin B-induced myelosuppression by antagonizing the suppressive effects of TNF and IFN and by enhancing the proliferative activity of BM.

The influenza virus variant A/FM/1/47-MA possesses single amino acid replacements in the hemagglutinin, controlling virulence, and in the matrix protein, controlling virulence as well as growth

Genetic analysis of mouse-adapted influenza virus variant A/FM/1/47 (FM) MA has previously identified four genome segments, 4, 5, 7, and 8, that are statistically associated with virulence. On sequencing these genome segments, we found single amino acid replacements at amino acid 47 of the HA2 subunit of the hemagglutinin and at amino acid 139 of the matrix protein. Mutation was not detected in segments 5 and 8, obviating a role for these genes in FM-MA virulence. FM-MA replicates to higher titer than FM in MDCK cells and in mouse lung. FM X FM-MA reassortants were used to show that the M1 gene controlled replication in MDCK cells as well as in mouse lung.

Use of polyethylene glycol-bound superoxide dismutase, polyethylene glycol-bound catalase, and nimodipine to prevent hypoxic ischemic injury to the brain of newborn pigs

OBJECTIVE

To determine if polyethylene glycol-bound superoxide dismutase and catalase and nimodipine, alone or in combination, will ameliorate hypoxic ischemic injury to the brain.

SUBJECTS

A total of 78 newborn (0 to 3 days) pigs were used.

DESIGN

Prospective, blinded, randomized, controlled trial.

INTERVENTIONS

The piglets were subjected to hypoxic ischemic brain injury. Carotid arteries were ligated at time 0 and BP was reduced one third by hemorrhage. At 15 mins, FIO2 was reduced to 0.6. At 30 mins, carotids were released, blood was reinfused, and FIO2 was increased to 1.0. Pigs were randomly assigned at time 35 mins to receive either: 10,000 U/kg of polyethylene glycol-bound superoxide dismutase and catalase (group 1); 0.5 mg/kg of nimodipine (group 2); both 10,000 U/kg of superoxide dismutase and catalase and 0.5 mg/kg of nimodipine (group 3); or no drugs (controls).

MEASUREMENTS

The time after reoxygenation for return of electroencephalogram, respiration, blink and pain were recorded in minutes as well as a neurologic examination at 1, 2, and 3 days and pathologic examination of the brain at 3 days, both by blinded observers.

MAIN RESULTS

There were no significant differences in the four groups.

CONCLUSIONS

Polyethylene glycol-bound superoxide dismutase and catalase, and nimodipine, either alone or in combination, do not ameliorate hypoxic ischemic injury to the brain in the newborn pig when given 5 mins after reoxygenation.

A novel approach to immunomodulation of frozen human bone marrow with interleukin-2 for clinical application

Interleukin-2 (IL-2) activation of fresh or frozen bone marrow (BM) in vitro generates killer cells with potent anti-tumor effect both in vitro and in vivo. The IL-2-activated BM (ABM) retains the capacity to reconstitute the hematopoietic system in an autologous bone marrow transplantation (ABMT) setting. The killer cells lose their cytotoxicity if the ABM undergoes the procedures of freezing and thawing. Therefore, for clinical application, the ABM has to be generated after thawing a frozen stock of BM before ABMT. The thawed BM cells are fragile and may undergo lysis, resulting in clump formation and cell loss. The frozen autograft also contains components of cryoprotectant mixture whose effects on the generation of ABM have not been defined. The present studies have been carried out to optimize a technique of handling the frozen BM for immunomodulation with IL-2 for 24 h at 37 degrees C prior to ABMT, with minimal loss of cells. IL-2-activation of BM was carried out in bags containing serum free medium which were designed to permit gaseous exchange. Addition of deoxyribonuclease (DNAse) (100 micrograms/ml of BM concentrate) immediately after thawing and the presence of heparin (20 units/ml) in the medium completely abrogated immediate or delayed clumping of cells. The presence of DNAse and/or heparin during in vitro culture did not affect the cell viability, cytotoxicity against tumor cells or the progenitor cell activity of the ABM; all these functions were well maintained even when BM was placed in culture immediately after thawing (without washing). There was no microbial contamination.(ABSTRACT TRUNCATED AT 250 WORDS)

Interference is controlled by segment 2 and possibly by segment 8 of the nondefective interfering influenza virus variant A/FM/1/47-MA

On mouse adaption of A/FM/1/47, a variant, A/FM/1/47-MA (FM-MA), that had acquired the properties of increased virulence and interference was produced. Coinfection of cells with FM-MA and prototype strains of influenza virus yielded > 100-fold more FM-MA virus than prototype virus, whereas coinfection with the same prototype strains and the parental A/FM/1/47 virus produced equivalent yields, indicating that FM-MA had acquired mutations that confer the property of interference during mouse adaption. FM-MA is a nondefective interfering virus that grows to a high titer in vivo and in vitro. It has previously been shown that segments 4, 7, and 8 and possibly segment 5 account for the increased virulence. In this study we show by genetic analysis of FM-MA x A/HK/1/68 reassortants that segment 2, coding for the polymerase-associated protein PB1, and possibly segment 8, encoding the NS1 and NS2 proteins, control the ability of FM-MA to interfere. Interference could not be overcome by increasing the titer of the coinfecting strain, but delaying FM-MA infection by 4 to 6 h did avoid interference. During interference of A/HK/1/68, protein synthesis was inhibited by less than 65% throughout coinfection. Given the kinetics of interference and the small perturbation in protein synthesis, interference appeared to occur at the level of late genome replication or virus assembly. Virulence and interference in FM-MA were not linked. An interfering avirulent FM-MA x A/HK/1/68 reassortant, E07, was capable of protecting mice against lethal pneumonia due to a virulent noninterfering reassortant, H04.

Fructose-1,6-bisphosphate does not ameliorate hypoxic ischemic injury to the central nervous system in the newborn pig

BACKGROUND AND METHODS

Fructose-1,6-bisphosphate has been shown to improve the outcome of hypoxic ischemic brain injury in adult rabbits. We wished to see if these results could be extended to a newborn animal. Twenty-four 0- to 3-day-old piglets were randomized to receive 300 mg/kg of fructose-1,6-bisphosphate 5 mins before injury, followed by a continuous infusion of 15 mg/kg/min of fructose-1,6-bisphosphate for the next 90 mins, or the equivalent volume of normal saline. Hypoxic ischemic central nervous system damage was induced by ligating both carotid arteries and reducing their BP to two thirds of the normal value for 30 mins. In the last 15 mins of this 30 mins, the FIO2 was reduced to 0.6. At 30 mins, the piglets were resuscitated with an FIO2 of 1.0, the carotid ligatures were released, and the removed blood was reinfused.

RESULTS

The neurologic examination scores at 1, 2, and 3 days after injury and pathologic examination scores at 3 days after injury were not different in the fructose-1,6-bisphosphate-treated and the control animals.

CONCLUSION

Fructose-1,6-bisphosphate does not ameliorate hypoxic ischemic brain injury in the newborn pig.

Nucleotide sequence comparison of the M1 genome segment of reovirus type 1 Lang and type 3 Dearing

The mammalian reoviruses possess a genome composed of 10 double stranded RNA segments. The serotype 1 strain Lang M1 segment was sequenced and compared to the published type 3 sequence. Both segments were 2304 base-pairs long coding for the mu 2 protein predicted to be 736 amino acids long. The sequences were highly conserved with 97.2% conservation of nucleotide sequence and 98.6% conservation of amino acid sequence. The M1 segments of serotypes 1 and 3 have recently diverged as indicated by the distribution of variation with respect to codon positions. The conservation of amino acid sequence indicated that the mu 2 protein has a relatively high functional density.